Phototherapy such as photothermal therapy and photodynamic therapy in cancer treatment has been developed quickly over the past few years for its noninvasive nature and high efficiency. However, ...there are still many drawbacks in phototherapy that prevent it from clinical applications. Thus, scientists have designed different systems to overcome the issues associated with phototherapy, including enhancing the targeting ability of phototherapy, low‐temperature photothermal therapy, replacing near‐infrared light with other excitation sources, and so on. This article discusses the problems and shortcomings encountered in the development of phototherapy and highlights possible solutions to address them so that phototherapy may become a useful cancer treatment approach in clinical practice. This article aims to give a brief summary about current research advancements in phototherapy research and provides a quick guideline toward future developments in the field.
This article discusses the issues and shortcomings encountered in the development of photodynamic and photothermal therapy and highlights possible solutions to address them so that phototherapy may become a useful cancer treatment approach in clinical practice.
A pandemic of Salmonella enterica serotype Enteritidis emerged in the 1980s due to contaminated poultry products. How Salmonella Enteritidis rapidly swept through continents remains a historical ...puzzle as the pathogen continues to cause outbreaks and poultry supply becomes globalized. We hypothesize that international trade of infected breeding stocks causes global spread of the pathogen. By integrating over 30,000 Salmonella Enteritidis genomes from 98 countries during 1949-2020 and international trade of live poultry from the 1980s to the late 2010s, we present multifaceted evidence that converges on a high likelihood, global scale, and extended protraction of Salmonella Enteritidis dissemination via centralized sourcing and international trade of breeding stocks. We discovered recent, genetically near-identical isolates from domestically raised poultry in North and South America. We obtained phylodynamic characteristics of global Salmonella Enteritidis populations that lend spatiotemporal support for its dispersal from centralized origins during the pandemic. We identified concordant patterns of international trade of breeding stocks and quantitatively established a driving role of the trade in the geographic dispersal of Salmonella Enteritidis, suggesting that the centralized origins were infected breeding stocks. Here we demonstrate the value of integrative and hypothesis-driven data mining in unravelling otherwise difficult-to-probe pathogen dissemination from hidden origins.
In this paper, an ultra-broadband and high-efficiency polarization conversion metasurface is presented in the terahertz region. The metasureface is similar to a sandwiched structure, which is ...composed of the top Double Split Ring Resonator (DSRR), an intermediate dielectric layer and a bottom metal layer. Both numerical simulation and theoretical calculation results demonstrate that the proposed metasurface can convert linearly co-polarized waves into cross-polarized waves in the frequency from 2.04 THz to 5.33 THz with a relative bandwidth of 89% and the polarization conversion ratio (PCR) is over 90%. Further simulation results show that the proposed metasurface is insensitive to the polarization angle, and the physical mechanism is revealed in detail by the surface current distribution. In addition, two different kinds of 2-bit coding metasurfaces are designed based on the Pancharatnam-Berry (PB) Phase. The simulated and calculated results show that the proposed PB-coding metasurface has excellent performance in flexibly controlling terahertz wave reflection and low Radar Cross Section (RCS). A 10dB RCS reduction can be achieved from 1.9 THz to 5.5 THz under normal incidence. It provides new degrees of freedom for studying terahertz wave manipulation and reducing RCS.
Image enhancement plays an important role in improving image quality in the field of image processing, which is achieved by highlighting useful information and suppressing redundant information in ...the image. In this paper, the development of image enhancement algorithms is surveyed. The purpose of our review is to provide relevant researchers with a comprehensive and systematic analysis on image enhancement techniques and give them a valuable reference. Various image enhancement algorithms were mentioned and underlying difficulties, limitations, merits and disadvantages were discussed in applying these techniques in the past two decades with three aspects: supervised algorithm, unsupervised algorithm and quality evaluation, respectively. Further, we summarize some existing problems and analyze the future development trend of existing enhanced algorithms.
The majority of existing image encryption algorithms use single chaotic systems, such as Logistic map or Lorentz system, to be the pseudo-random sequence generator. Actually, neither low nor high ...dimensional chaotic system can get rid of pseudo-randomness deterioration of chaotic sequence calculated by limited precision computer. Additionally, most of them use only one chaotic pseudo-random sequence throughout the encryption process. These are the more obvious deficiencies. In the current paper, a novel compound chaotic system is applied to color images domain to solve the mentioned problems. Dynamic parameter-control chaotic system can enhance the sequence’s randomness after digitalizing. Corresponding the different sequences generated by the novel chaotic system to each color channel of image is a helpful method to reduce the image’s statistical characteristics in the scrambling process. Finally, the effectiveness and security of the proposed encryption has been illustrated by the experimental, and at the meantime, excellent performance is also demonstrated.
The pulse-coupled neural network (PCNN) is widely used in digital image processing. Although existing studies mainly analyze the network from the time-domain perspective, there are still some ...limitations in revealing the characteristics of network. In this paper, from the iterative equations of PCNN, the expressions for the firing time and firing interval of neuron are given. Spectrum for the dynamic threshold subsystem and firing subsystem of PCNN is given by using the Z-transform and the discrete Fourier transform, and the effects of different parameters
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on the frequency-domain characteristics of the two subsystems are analyzed. The edge detection phenomenon exhibited by the iterative output of the PCNN is explained by analyzing the effect of the neighbor coupling state on the firing time and interval. Finally, the correctness of the analysis is validated by simulation experiments, which provides a new idea for the further study into the characteristics of PCNN.
Information security has become a focal topic in the information and digital age. How to realize secure transmission and the secure storage of image data is a major research focus of information ...security. Aiming at this hot topic, in order to improve the security of image data transmission, this paper proposes an image encryption algorithm based on improved Arnold transform and a chaotic pulse-coupled neural network. Firstly, the oscillatory reset voltage is introduced into the uncoupled impulse neural network, which makes the uncoupled impulse neural network exhibit chaotic characteristics. The chaotic sequence is generated by multiple iterations of the chaotic pulse-coupled neural network, and then the image is pre-encrypted by XOR operation with the generated chaotic sequence. Secondly, using the improved Arnold transform, the pre-encrypted image is scrambled to further improve the scrambling degree and encryption effect of the pre-encrypted image so as to obtain the final ciphertext image. Finally, the security analysis and experimental simulation of the encrypted image are carried out. The results of quantitative evaluation show that the proposed algorithm has a better encryption effect than the partial encryption algorithm. The algorithm is highly sensitive to keys and plaintexts, has a large key space, and can effectively resist differential attacks and attacks such as noise and clipping.
It is well recognized that Salmonella can survive long-term starvation and desiccation stresses and contaminate foods that have intermediate to low water activities; however, little is known about ...the specific molecular mechanisms underlying its survival and persistence in low water activity foods. In this study, we used the RNA-seq approach to compare the transcriptomes (27–33 million 36-bp reads per sample) of a Salmonella enterica subsp. enteric serovar Enteritidis strain ATCC BAA-1045 after inoculation in peanut oil (water activity 0.30) for 72 h, 216 h and 528 h to those grown in Luria-Bertani (LB) broth for 12 h and 312 h. Our results showed that desiccated Salmonella cells in peanut oil were in a physiologically dormant state with <5% of its genome being transcribed compared to 78% in LB broth. Among the few detected transcripts in peanut oil, genes involved in heat and cold shock response, DNA protection and regulatory functions likely play roles in cross protecting Salmonella from desiccation and starvation stresses. In addition, non-coding RNAs may also play roles in Salmonella desiccation stress response. This is the first report of using RNA-seq technology in characterizing bacterial transcriptomes in a food matrix.
► Molecular mechanisms of Salmonella desiccation stress response are explored. ► RNA-seq is used to profile Salmonella Enteritidis transcriptome in peanut oil and LB. ► S. Enteritidis subjected to prolonged desiccation possesses limited transcriptomic activity. ► Heat and cold shock proteins cross protect Salmonella from desiccation. ► First use of RNA-seq in characterizing a bacterial transcriptome associated with a food matrix.
The current research aimed to explore the possible relationship between PINK1/PARKIN‐mediated mitophagy and the compression‐induced senescence of nucleus pulposus cells (NPCs). Therefore, the stages ...of senescence in NPCs were measured under compression lasting 0, 24 and 48 hours. The mitophagy‐related markers, autophagosomes and mitochondrial membrane potential were tested to determine the levels of PINK1/PARKIN‐mediated mitophagy under compression. The PINK1 and PARKIN levels were also measured by immunohistochemistry of human and rat intervertebral disc (IVD) tissues taken at different degenerative stages. A specific mitophagy inhibitor, cyclosporine A (CSA) and a constructed PINK1‐shRNA were used to explore the relationship between mitophagy and senescence by down‐regulating the PINK1/PARKIN‐mediated mitophagy levels. Our results indicated that compression significantly enhanced the senescence of NPCs in a time‐dependent manner. Also, PINK1/PARKIN‐mediated mitophagy was found to be activated by the extended duration of compression on NPCs as well as the increased degenerative stages of IVD tissues. After inhibition of PINK1/PARKIN‐mediated mitophagy by CSA and PINK1‐shRNA, the senescence of NPCs induced by compression was strongly rescued. Hence, the excessive degradation of mitochondria in NPCs by mitophagy under continuous compression may accelerate the senescence of NPCs. Regulating PINK1/PARKIN‐mediated mitophagy might be a potential therapeutic treatment for IVD degeneration.
Comparisons among a qPCR assay, VIDAS® assays and a conventional agar streaking method following the same enrichment for the detection of Listeria monocytogenes were performed under two challenging ...conditions. In the first comparison, L. innocua and L. monocytogenes were coinoculated into sausages at ratios (L. innocua-to-L. monocytogenes) of 10, 100, 1000, and 10 000. qPCR provided the most sensitive detection at all ratios after both 24-h and 48-h enrichments. A modified VIDAS® LMO2 assay (i.e., replacement of the kit-specified enrichment scheme with the enrichment scheme used in this study) and agar streaking yielded equivalent results when the ratio was 10 and 100; agar streaking was more sensitive when the ratio was 1000; neither method could detect L. monocytogenes at the ratio of 10 000. Enrichment duration of 48 h was needed for modified VIDAS® to detect L. monocytogenes when the ratio was 1000. Agar streaking after 24-h enrichment isolated L. monocytogenes better than after 48-h enrichment when the ratio was 100 and 1000. In the second comparison, we followed the validation guidelines of AOAC International and inoculated L. monocytogenes, without any L. innocua, onto lettuce and stainless-steel surfaces at low levels. The numbers of positive samples detected by qPCR, VIDAS® LIS assay, modified VIDAS® LMO2 assay, and agar streaking after 48-h enrichment were not statistically different. Our data showed that qPCR was the most sensitive method, while agar streaking and VIDAS® performed reasonably well. Streaking after 24-h enrichment was needed when background flora could overgrow L. monocytogenes during prolonged enrichment, and this is critical for confirming rapid screening assays. Appropriate selection of enrichment duration and rapid assays will enhance the testing of L. monocytogenes in food and environmental samples.
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